Comparison of Sulfates and TDS in Monitor Wells along Impoundment and Off-Site

Sierrita Impoundment Water

Date

Hardness

as CaCO3

Calcium mg/l

Magnesium mg/l

Sulfate

Arsenic mg/l

TDS

pH

Units

12/17/79

 

631

<1

1,806

 

2,856

9.2

12/02/80

 

608

5

1,842

 

2,885

9.4

11/23/81

 

601

7

1,948

 

3,011

9.3

11/02/88 

 

640 

.08 

1,720 

 

3,280 

10.9 

1989

 

655

.63

1,910

 

3,300

10.27

 

Monitor Wells along Impoundment from N to S

 

MH-3 North End of Impoundment (2/76; 520 ft)

Date

Hardness

as CaCO3

Calcium mg/l

Magnesium mg/l

Sulfate

Arsenic mg/l

TDS

pH

Units

4/25/79*

 

 

 

482

 

1,000

 

4/22/80*

 

 

 

475

 

955

 

4/24/81*

 

 

 

480

 

1,000

 

4/30/82*

 

 

 

470

 

960

 

6/25/97

 

171

35.7

440

 

940

7.4

9/30/97

 

168

35.5

460

 

900

7.7

4/4/01

 

478

106

1,650

 

2,660

7.3

12/6/04

 

 

 

1,660

 

 

 

 

MH-14 North End of Impoundment (near MH-3)

Date

Hardness

 

Calcium mg/l

Magnesium mg/l

Sulfate

Arsenic mc/l

TDS

pH

units

8/31/90

 

370

82

1,125

 

1,930

7.5

10/8/90

 

320

80

961

 

1,756

7.11

9/9/91

 

360

75

1,034

 

2,052

7.13

8/14/92

 

300

71.6

1,095

<.01

1,862

7.08

9/16/93

 

360

79.5

1,349

 

2,170

7.07

 

 

 

 

 

 

 

 

7/29/97

 

420

82

1,160

 

2,220

7.6

6/19/98

 

419

84.3

1,110

 

2,160

6.9

12/04/98

 

427

93.4

1,340

 

2,330

6.8

7/5/00

 

443

96.1

1,390

 

2,400

7.5

4/2/01

 

451

98.1

1,550

 

2,550

7.2

4/15/02

 

440

99.1

1,430

 

2,490

6.7

4/22/03

 

429

92.7

1,370

 

2,410

7.4

6/28/04

 

445

102

1,480

 

2,590

7.4

1/30/06

 

 

 

1,500

 

 

 

 

MH-4 One Quarter Mark�North Half of Impoundment (3/76; 550 ft)

Date

Hardness

as CaCO3

Calcium mg/l

Magnesium mg/l

Sulfate

Arsenic mg/l

TDS

pH

Units

/25/97

 

427

54.7

1,260

 

2,210

7.6

9/23/97

 

600

58.8

1,650

 

2,900

7.6

4/5/01

 

 

 

2,090

 

 

 

 

MH-5 Half-Point of Impoundment (3/76; 640 ft.)

Date

Hardness

as CaCO3

Calcium mg/l

Magnesium mg/l

Sulfate

Arsenic mg/l

TDS

pH

Units

4/25/79*

 

 

 

1,435

 

2,350

 

4/22/80*

 

 

 

1,440

 

2,400

 

4/24/81*

 

 

 

1,445

 

2,760

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